ISSUE: FDA is advising the public about strengthened and updated warnings regarding neurologic and psychiatric side effects associated with the antimalarial drug mefloquine hydrochloride. A boxed warning, the most serious kind of warning about these potential problems, has been added to the drug label. FDA has revised the patient Medication Guide dispensed with each prescription and wallet card to include this information and the possibility that the neurologic side effects may persist or become permanent. The neurologic side effects can include dizziness, loss of balance, or ringing in the ears. The psychiatric side effects can include feeling anxious, mistrustful, depressed, or having hallucinations.

Neurologic side effects can occur at any time during drug use, and can last for months to years after the drug is stopped or can be permanent. See the Drug Safety Communication for more information, including a data summary.

BACKGROUND: Mefloquine hydrochloride is indicated for the treatment of mild to moderate acute malaria caused by mefloquine-susceptible P. falciparum and P. vivax, and prevention of malaria infections by P. falciparum (including chloroquine-resistant P. falciparum) and P. vivax. It was previously marketed under the brand name Lariam; however, the Lariam product is not currently marketed. Generic mefloquine products are available in the US.

RECOMMENDATION: Patients, caregivers, and health care professionals should watch for these side effects. When using the drug to prevent malaria, if a patient develops neurologic or psychiatric symptoms, mefloquine should be stopped, and an alternate medicine should be used. If a patient develops neurologic or psychiatric symptoms while on mefloquine, the patient should contact the prescribing health care professional. The patient should not stop taking mefloquine before discussing symptoms with the health care professional.

For additional information for health care professionals and patients, refer to the Drug Safety Communication.

Healthcare professionals and patients are encouraged to report adverse events or side effects related to the use of these products to the FDA's MedWatch Safety Information and Adverse Event Reporting Program: